1. Field of the Invention
To correct unbalance of a rotary member such as a wheel and more especially a motor vehicle wheel, one or more compensating or balancing weights such as adhesive weights can be secured to the rotary member or wheel in an appropriate position as is ascertained by electronic measurement during an unbalance measuring procedure. A form of balancing machine for use in such a method may include an apparatus for sensing geometrical data of the rotary member to be balanced, which can be clamped on a main shaft of the balancing machine, the sensing apparatus having a measuring sensor for the sensing operation, which measuring sensor is carried on a support bar of the balancing machine, which is parallel to the main shaft, with the sensor being rotatable about the longitudinal axis of the support bar.
2. Description of the Related Art
A balancing machine of that kind is known from the Hofmann operating instructions for the Geodyna 88/88 m wheel balancing machine, imprint 9412145-09.86. That machine has a main body structure which carries a left-hand measuring sensor for ascertaining the spacing, relative to the machine, of the left-hand rim flange of a wheel which is clamped in position on the machine, and a right-hand measuring sensor for ascertaining the dimension in respect of the right-hand wheel rim flange. A measuring lever of the right-hand measuring sensor is carried on a separate support or guide bar, pivotably about the longitudinal axis thereof. The support bar is parallel to a fixing axis of a wheel guard hood and is longitudinally movable relative to the main body structure of the balancing machine. For the purposes of width measurement, that is to say for sensing the right-hand side of a rim of a wheel which is clamped in position, more specifically the right-hand balancing plane of the wheel rim, the measuring lever is moved with its measuring finger into a measurement position by the measuring lever being moved with the support bar lengthwise towards the rim and being rotated about the longitudinal axis of the support bar.
In another method of compensating for unbalance on a motor vehicle wheel, as described in German patent application No P 42 29 865.2 corresponding to U.S. patent application Ser. No. 08/115,779, a sensing apparatus which is in the forth of a sensing lever or sensing bar is employed for mechanically sensing dimensions of the wheel rim and for moving the balancing weight into its balancing position on the wheel. That sensing apparatus is carried on the main body structure of the balancing machine but it may be used only for sensing the wheel rim at the machine side, that is to say, on the left-hand side of the wheel when viewing it from the front.
Another procedure as described in German published specification (DE-AS) No 2 001 972 or the above-mentioned Hofmann operating instructions for the Geodyna 88/88 m wheel balancing machine, imprint 9412145-09.86, involves ascertaining dimensions in particular in the rim region of a motor vehicle wheel, by means of a sensing apparatus, and storing such dimensions in an electronic measuring system. In that way suitable information is supplied to the electronic measuring system for calculating the sizes and angular positions required for the balancing weights which are to be mounted to the disk portion of the motor vehicle wheel at the appropriate balancing planes thereof. In a standard balancing procedure, that is to say when balancing weights are applied to the wheel rim flange or bead portions, it is possible, as disclosed in German laid-open application (DE-OS) No 27 37 524, for the nominal values which are specified on the motor vehicle wheel in respect of the geometrical dimensions thereof to be combined with a correction value, upon being inputted into the storage means of the electronic measuring apparatus, in order thereby to take account of the axial spacing of the center of gravity of the balancing weight, in the respective balancing plane. Reference may also be directed in this respect to German patent application No P 41 22 844 corresponding to U.S. patent application Ser. No 07/910,917 describing a sensing device which makes it possible to accurately ascertain the dimensions of the disk wheel or more specifically the rim portion thereof, in the balancing planes, for the input of those dimensions into the electronic measuring system, prior to carrying out the unbalance measuring operation.